This project aims to exploit the olfactory system of rodents in basic studies of brain mechanisms involved in mammalian learning and memory. Instead of studying learning and memory as they are traditionally defined by psychologists, the focus is upon instances of neurobehavioral plasticity of a kind upon which experimental acquisition and retention of responses are presumed to depend. The main lines of research are being pursued concurrently. In the first, the olfactory system is being studied as a 'simple cortical system' which exhibits changes in function (electrophysiological unit and slow-wave activity) in response to low-level electrical stimulation and which shows alterations in its structure (morphological rearrangement of fiber pathways) in response to surgical manipulation. The second line of research is concerned with behavioral and electrophysiological responses to olfactory stimuli. The objective, more specifically, is to shed light on the role of complex organic orders ('pheromones') in behavior patterns upon which individual and species survival depend. Particular attention is being paid to studies of species-specific activities (mating, social behavior, etc.) and to the relations between olfaction and neuroendocrine function. The project involves behavioral, anatomical and electrophysiological experiments and attempts to understand how changes in the mammalian central nervous system correlate with changes in an organism's responses to environmental and/or physiological stimuli.